Sen. John Cornyn, R-Texas, made the call for Holder's resignation during a Senate hearing late Tuesday morning. It came in the context of GOP concerns about Holder's decision to appoint two lawyers from within his department to handle the politically sensitive leak probe -- as well as concerns about Fast and Furious.

"I would say that you leave me no alternative but to join those that call upon you to resign your office," Cornyn said. "Americans deserve an attorney general that will be honest with them, they deserve an attorney general who will uphold the basic standards of political independence and accountability. You've proven time and time again, sadly, that you're unwilling to do so."

Holder in response accused Republicans of playing politics, and specifically accused Cornyn of "breathtaking" inaccuracies.